The present invention relates to a lock cylinder for a door lock and, more particularly, to a lock cylinder mounted to an outer operating device of a door lock to permit or not permit the outer operating device to unlatch a latch of the door lock.
Door locks have various types according to conditions, situations, and needs. Many of the door locks generally include an outer operating device mounted to an outer side of a door and operatively connected to a latch of the door lock. Operation of a handle of the outer operating device can retract the latch from a latching position to an unlatching position. The outer operating device generally includes a lock cylinder that can be operated to control the outer operating device to be in a locking state or an unlocking state. When the outer operating device is in the locking state, the latch cannot be unlatched by operation of the handle unless a key is inserted into a lock core in the lock cylinder to unlock the outer operating device.
However, whether the outer operating device is in the locking or unlocking state, the key can be separated from the lock core of the lock cylinder if the lock core is in its initial position. Furthermore, the lock core can be rotated to the initial position whether the outer operating device is in the locking or unlocking state. Namely, the key can be separated from the lock core even if a user forgets to lock the outer operating device. Thus, the user may forget to lock the outer operating device, or the user has to operate the handle of the outer operating device to make sure whether the outer operating device is locked.